In recent years, a miniaturization has quickly been progressed by the development of a lithographic technique in the field of microfabrication for production of semiconductor devices or liquid crystal devices. As such a microfabrication technique, the conversion of an exposure source into a source with a short wavelength has generally been used. Specifically, previous ultraviolet rays including g-line and i-line as a typical example have been changed to DUV.
Presently, a KrF excimer laser (248 nm) lithographic technique has been introduced in the market, and an ArF excimer laser (193 nm) lithographic technique, which is directed towards the conversion of an exposure source into that with a further shorter wavelength, is being introduced. Moreover, an F2 excimer laser (157 nm) lithographic technique is being studied as a technique for the next generation. Furthermore, an electron beam lithographic technique, which somewhat differs from the above techniques, is also intensively being studied.
As a resist with high resolution for such a light source with a short wavelength or electron beam, a “chemically amplified resist” has been proposed by International Business Machine (IBM) Corporation, and at present, the improvement and development of this chemically amplified resist has vigorously been progressing.
Resins used for resist are also forced to change their structure with the conversion of an exposure source into that with a short wavelength. In the KrF excimer laser lithography, employed is polyhydroxystyrene or polyhydroxystyrene with its hydroxyl group protected with an acid-deprotectable solubility-inhibiting group that is highly transparent to the light at 248 nm. In the ArF excimer laser lithography, it is almost impossible to use the above resin due to insufficient transparency to the light at 193 nm. Accordingly, acryl resins and cycloolefin resins transparent to the light at 193 nm attract attention. Examples of acryl resins include those described in Japanese Patent Laid-Open Nos. 4-39665, 10-207069 and others, and examples of cycloolefin resins include those described in Japanese Patent Laid-Open No. 10-153864 and others.
However, these resins are still insufficient in their performances, and further higher dry etching resistance is required.
As a photoresist for the ArF excimer laser, Japanese Patent Laid-Open No. 11-212265 describes a resin comprising a monomer unit derived from 2-alkyl-2-adamantyl (meth)acrylate and a monomer unit derived from itaconic anhydride, and Japanese Patent Laid-Open No. 2000-26446 describes a resin obtained by (co)polymerization of (meth)acrylate derivatives having polycyclic lactone groups. These publications describe that these resins are excellent in an adhesive property to a substrate and etching resistance, but these are irrelevant to the feature of the present invention.